This invention relates generally to apparatus and methods used by telephone technicians in testing and repairing telephone lines in the field. The invention relates more particularly to remote assist apparatus and methods that enable a telephone technician to control a junction in a telephone line from a remote location along the line.
A telephone line, as that term is used in this description and the following claims, includes a pair of wires in which one wire is referred to as the tip wire or side and the other as the ring wire or side (this terminology is used throughout the following description and claims and encompasses other terms that may be used in the industry; for example, "tip" encompasses the European "A" or "A side" and "ring" encompasses the European "B" or "B side"). These wires are typically individually insulated but twisted together to form a conventional twisted pair telephone line. Such a telephone line extends between a central office and a subscriber as illustrated in FIG. 1.
At least some segments of a typical telephone line are in respective cables that include other twisted wire pairs. Such cables also have outer shields that are earth grounded when the cables are installed. Referring to FIG. 1, an underground feeder cable 2 extends from a main distribution frame 4 connected to class 5 switching equipment 6 in a central office 8. The cable 2 has several twisted wire pairs, each defining a segment of a respective telephone line. Each of these segments terminates in the illustrated cross-connect box 12 in the field, such as may be located at a residential neighborhood. These can be connected at the cross-connect box 12 to other respective twisted wire pairs defining other segments of the telephone lines. In FIG. 1 these other segments are within a distribution cable 14 that extends from the junction in the cross-connect box into the neighborhood in this example. One or more such segments can end, for example, at a pedestal or aerial terminal box 16. A further segment of a respective twisted pair telephone line is a drop cable 18 extending from the junction at the pedestal or aerial terminal box 16 to a residential network interface box 20 at the subscriber site, such as house 22. The length of such a telephone line can be from several hundred feet to a few miles, for example.
When a subscriber reports a problem with his or her telephone service, the local telephone company performs tests on the circuit. Some of these tests may be internal, that is, from the central office or further upstream away from the telephone line extending into the field described above. Some tests, however, may need to be performed in the field along the telephone line. To make such field tests, a telephone technician works with the segments to try to determine which, if any, segment is causing the problem. For example, the technician might drive to the cross-connect box, disconnect the junction formed there between the respective telephone line segment in the feeder cable and the respective telephone line segment in the distribution cable, and perform tests on the segment directed toward the central office side and on the segment directed toward the subscriber side. These tests are well-known in the industry and can include forming different terminations on the tip and ring wires of the respective segment (e.g., grounding the tip and ring wires or shorting the tip and ring wires together). Some such testing can be performed with the technician's conventional butt-set; more extensive testing can be performed with other known test devices. One such device is marketed under the trademark "PairChek" by Communications Manufacturing Company of Los Angeles, Calif.
If the problem is in the portion of the telephone line extending between the cross-connect box and the subscriber in the example of FIG. 1, the technician will want to continue testing in segments to isolate the source of the problem. To test the segment between the cross-connect box and the pedestal or aerial terminal box, the technician can configure the cross-connect box end of the respective segment, drive to the pedestal or aerial location, perform the test from that end, return to the cross-connect box, and repeat the process for whatever tests and different configurations are needed. This, obviously, is very time consuming and costly. It can also leave the subscriber disconnected for extended periods. One way to reduce the time is to use a second technician so that one can work at each end of a segment; however, this is costly and requires good communication between the two technicians. Another way to reduce both the time and cost is to use an electronic apparatus at the end of any segment opposite the technician, which apparatus communicates with a test device used by the technician at his or her end of the segment.
One such electronic apparatus is the SmartStrap.RTM. cable test/remote strapping device from Communications Technology Corporation of Madison, Ala. This device connects to one end of a segment of a tip and ring wire pair and to a second telephone line over which control signals can be received. Despite this device, there is the need for a telephone technician's remote assist apparatus and method for use in testing a telephone line that enable both control and testing to occur over the same telephone line. This need is imperative in some environments, such as for a rural subscriber where only a single pair of wires is available. There is also the need for specialized control signal encoding whereby other automated response features connected to the telephone line are not activated by the control signals for the remote assist apparatus or method. Yet another need is for automated (i.e., without further external control) restoration of the telephone line so that the subscriber is not left disconnected once a test is completed.